Puffer piston gas blast circuit interrupter with insulating nozzle member and valve acting hollow contacts

ABSTRACT

A GAS-BLAST CIRCUIT INTERRUPTER OF THE PUFFER PISTON TYPE IS PROVIDED HAVING A PAIR OF VENTED SEPARABLE CONTACTS, WHICH MAKE VALVE-CLOSED ENGAGEMENT IN THE CLOSED POSITION. AN OPERATING LINKAGE IS PROVIDED WITH A LOST MOTION MECHANICAL CONNECTION BETWEEN THE PISTON MEANS AND THE MOVING CONTACT, SO THAT GAS PRESSURE IS BUILT UP PRIOR TO CONTACT PART. THE CONTACTS SEPARATE WITHIN AN INSULATING NOZZLE MEMBER, WHICH   GUIDES ALL OF THE GAS FLOW THROUGH BOTH VENTED CONTACTS, WHEN THEY PART DUE TO THE TAKEUP OF THE LOST MOTION.

United States Patent OPEN\ 3,339,046 8/1967 Giammona et a1 ZOO/148(B)2,442,010 5/1948 Leeds et al 200/150(G) 2,757,261 7/1956 Lingal et a1.ZOO/148(2) 3,095,490 6/1963 Cromer et al... 200/148(.1) 3,291,94712/1966 Van Sickle ZOO/148(8) FOREIGN PATENTS 144,768 9/1935 Austria200/l48(.1) 106,334 7/1938 Austria 200/148(.I) 369,189 9/1930 GreatBritain..... 200/l48(.1) 514,359 1/1938 Great Britain 200/148(.l)

Primary ExaminerRobert S. Macon Assistant ExaminerRobert A. VanderhyeAttorneys-A. T. Stratton, Clement L. McI-Iale and W. R.

Crout ABSTRACT: A gas-blast circuit interrupter of the puffer pistontype is provided having a pair of vented separable contacts, which makevalve-closed engagement in the closed position. An operating linkage isprovided with a lost motion mechanical connection between the pistonmeans and the moving contact, so that gas pressure is built up prior tocontact part. The contacts separate within an insulating nozzle member,which guides all of the gas flow through both vented contacts, when theypart due to the takeup of the lost motion.

PATENTED-JUNZSIHYI 3,5 9,407

sum 1 OF 3 l p FIG-l.

WITNESSES IN TORS ATTORNEY PUFFER PISTON GAS BLAST CIRCUIT INTERRUP'I'ERWITH INSULATING NOZZLE MEMBER AND VALVE ACTING HOLLOW CONTACTS CROSSREFERENCES TO RELATED APPLICATIONS Applicants are not aware of anyrelated pending patent applications pertinent to the present invention.

BACKGROUND OF THE INVENTION The invention relates to a puffer, orpiston-type fluid-blast circuit interrupter in which a piston structure,providing a fluid blast, is related to the operating mechanism andprovides a desirable fluid-blasting action during contact separation,with the fluid flow passing over the arc to effect its extinction.Cromer et al. U.S. Pat. No. 3,095,490 teaches, generally, a fluid-blastcircuit interrupter of such a type in which the separation of thecontact structure is deliberately delayed until a predetermined pressurebuildup occurs. This has the advantage of providing an adequate pressuredifferential across a related orifice structure prior to contact part.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment ofthe invention, there is provided an elongated insulating housingstructure, interiorly of which is disposed a movable operating cylinderconnected by a lost-motion mechanical connection to the movable contactstructure. The movable operating cylinder has a closed end portion andslides over a stationary piston, which supports the stationary contactstructure. Because of the provision of the lost-motion mechanicalconnection, there occurs a predetennined pressure buildup prior tocontact part. The stationary and movable contacts are so arranged as toblock off any venting of the gas flow during the taking up of thelost-motion during the initial portion of the Opening operation. Whenthe lost-motion has been taken up, there occurs a separation of theseparable contact structure and a consequent exhausting of fluid flow inopposite directions through the stationary tubular vented contact, andalso in an opposite direction through the movable tubular vented movingcontact so that an opposite double-fluid flow is achieved. A coolingstructure surrounds the vented stationary contact and assures thereby acooling of the compressed gas prior to its ejection through the are.

A general object of the present invention is to provide an improveddelayed-action piston-type fluid-flow circuit interrupter in which apressure buildup is achieved prior to contact part, and then a highlyeffective double-flow exhausting action is achieved.

Still a further object of the present invention is the provision of alow-cost fluid-blast circuit interrupter of highly efficientconstruction and operation.

Still a further object of the present invention is the provision of ahighly effective delayed-action piston-type circuit interrupter in whichcooled gas under pressure is ejected into the arcing region; and then adouble-flow exhausting action is obtained for rapid arc elongation andefi'ective fluid flow.

Further objects and advantages will readily become apparent upon readingthe following specification, taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a perspective viewof a three-pole circuit interrupter embodying the principles of thepresent invention;

FIG. 2 is a longitudinal sectional view taken through one of theinterrupting assemblies of FIG. 1, the contact structure beingillustrated in the closed-circuit position;

FIG. 3 is a view similar to that of FIG. 2, but illustrating thedisposition of the several parts at an intermediate point in the openingoperation;

FIG. 4 is a sectional view taken substantially along the line IV-IV ofFIG. 2; and

FIG. 5 is a sectional view taken substantially along the line V-V ofFIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, andmore particularly to FIG. 1 thereof, a reference numeral 1 generallydesignates a threepole fluid-blast circuit interrupter comprising threespaced pole assemblies A, B and C. As will be apparent from FIG. I, eachpole assembly includes, generally, an upper end plate 2, a generallyupstanding cylindrical housing 3, and a lower end plate and mechanismhousing 4. Disposed exteriorly of the mechanism housing 4 is a drivecrank 5 affixed to an operating shaft 6, and a generally horizontallyreciprocally movable insulating operating rod 7 is pivotally secured tothe external operating crank 5, as at 8, and is connected to a drivecrank 9 through a pivotal connection 10. The three drive cranks 9, onlyone of which is shown, are affixed and rotatable with an operating driveshaft II, which is connected to a suitable mechanism 12, whichconstitutes no part of the present invention, and may be of the type setforth in U.S. Pat. No. 3,183,332, issued May ll, I965 to Russell E.Frink and Paul Olsson, and assigned to the assignee of the presentinvention.

It will be apparent from FIG. I that a suitable supporting groundedframework 14 is utilized comprising vertical channels members 15 withinterbracing structural steel members I6, having horizontally extendinginsulating support straps 16b secured thereto, which assist insupporting the interrupting assemblies. Additionally, lower insulatorsupports 17 may be employed extending generally horizontally from achannel support member 160, the latter being affixed to the verticalsupport channels 15.

FIGS. 2 and 3 more clearly illustrate the internal construction of eachof the interrupting assemblies. With reference to FIG. 2, it will benoted that there is provided the cylindrical housing 3 of a suitableinsulating material having at one end thereof the end closure plate 2having a line terminal connection 20 constituting an integral partthereof. At the opposite end of the tubular housing 3 is the operatingcasting 4, within which extends the rotatable operating shaft 6 havingaffixed thereto. as by a key pin I8, an internally disposed operatingcrank 19, the latter being pivotally connected, as at 20, to a pair ofmetallic operating links 21. The upper ends of the operating links 21,as viewed in FIGS. 2, 3, and 5 are pivotally connected to a pivot pin22, the latter extending through apertures 23 provided in a spiderlikespring seat 24, which is fastened, as by pins 25, to the end 26a of amovable operating cylinder 26 having a closed end plate portion 26b.Interposed between the spiderlike spring seat support 24, movable withthe movable operating cylinder 26, is a contact compression spring 27having its upper end 27a bearing upon a generally frustoconical movablespring seat support 28 constituting an integral part of an elongatedmovable tubular vented contact rod 30. The contact rod 30 makes slidingcontacting engagement, as at 3I, with a stationary sliding contactstructure having a plurality of contact balls 33 interposed between asurrounding housing cage 34 and the outer surface 300 of the movabletubular contact 30. U.S. Pat. No. 3,301,986 illustrates the generalconstruction of such a stationary sliding contact structure.

At the upper end of the movable tubular contact rod 30 is a plurality ofcontact fingers 35 fomied by slotting the upper end of the movabletubular contact tube 30. Interiorly of the contact tube 30, as at 36, isa metallic orifice contact member 37 threaded, as at 38, to the outermovable contact tube 30. This movable metallic orifice member 37, havingan arc-resisting tip portion 370, abuts an arc-resisting stationaryorifice contact member 40, with a valve sealing engagement. The orificecontact member 40 is affixed to a stationary tubular contact tube 41which supports a fixed piston structure 43.

Preferably, the gas disposed within the interrupting housing 3 issulfiir-hexafluoride (SF gas, under a pressure of say, for example, 60p.s.i.

In more detail, the fixed piston 43 comprises a cup-shaped member 43ahaving apertures 43b therethrough and a cooling means 45 comprising aspirally arranged metallic strap 46, such as a copper strap, cooling thegas prior to its ejection into the arcing region 48. In other words, aswill be obvious. downward opening motion of the end closure plateportion 26b of the operating cylinder 26 will effect a compression ofthe gas within the region 50 and cause the ejection thereof through theapertures 43!: provided in the fixed piston 43 and into the arcingregion 48 following contact separation. Because of the provision of alostmotion connection 52 between the operating cylinder 26 and themovable contact structure 54, as brought about by the pivot pin 22moving through an elongated slot 55 provided in the sidewalls of themovable contact tube 30, there will be a predetermined pressure buildupwithin the region 50 prior to the taking up of the lost-motion 52 and amovement of the entire assembly 51 comprising the operating cylinder 26and the movable contact structure 54. When this occurs, the compressedgas within the region 50 will be forced through the cooling structure 45and into the arcing region 48 (FIG. 3) to become exhausted in oppositedirections through the fixed tubular vented contact tube 41 and also inan opposite direction through the movable vented tubular contact tube30, as illustrated more clearly in FIG. 3 of the drawings.

The stationary contact tube 41 is threadedly secured to a contactclamping plate 56, which is bolted, as by means of bolts 58, which passthrough spacing sleeves 59 and have their ends threaded into tappedholes 61 provided in the end metallic terminal plate 2. Additionally, adeflecting button 63 is provided, being threadedly secured to the endclosure plate 2 and serves to deflect the exhaust gases, as indicated bythe arrows 65 in FIG. 3 of the drawings.

The exhaust gases which pass through the moveable tubular contact rod 30are exhausted out of the end 30a thereof, and into the operatingmechanism casting 4 to become cooled.

It will be observed that the compression spring 27 not only assists inproviding the desired lost-motion connection 52 between the operatingcylinder 26 and the movable contact structure 54, but additionallyprovides the desired contact pressure in the closed-circuit position ofthe device, as is illustrated in FIG. 2 of the drawings.

With reference to FIGS. 2 and 3 of the drawings, it will be observedthat the stationary venting contact 40 is provided on the upstream sideof an electrically insulating arc chamber or flow guide 67, which issecured to the fixed piston 43, an apertured clamping plate 68 providedtherebetween, which assists in supporting the cooling coils of copperstrap 46, for example, within the cooling structure 45.

Additional support for the fixed piston structure 43 is provided bystationary support rods 69, which extend through the end clamping plate56 and are affixed to the end closure plate From the foregoingdescription, it will be apparent that counterclockwise rotative openingmotion of the operating shaft 6, as effected by the operating mechanism12 (FIG. 1), will cause, through the pair of links 21, downwardcompressing action of the operating cylinder 26 over the fixed piston43. This action will continue while the contact structure 54 remains inengagement with fixed contact 40 until the pivot pin 22 reaches thelower end of the elongated slots 55 provided in the opposite sidewallsof the movable contact tube 30. When this occurs, the pivot pin 22,being driven by the operating links 21, will cause downward followingopening motion of both the operating cylinder 26 and the movable contactstructure 54. By this time, however, there has been considerable gaspressure built up within the region 50, and upon the subsequent contactpart of the movable and stationary contacts 40, 54, the gas will passthrough the cooling means 45 and into the arcing region 48 (FIG. 3) toeffect are elongation 60 within the separating movable and stationarycontact orifice members 37 and 40, for rapid arc elongation and areextinction, the gas-exhausting action occurring in opposite directionsout through the stationary tubular venting contact post 41 and themovable tubular venting contact tube 30. Following arc extinction, themovable contact structure .54 and operating cylinder 26 moves to thefully open-circuit position, as illustrated by the dotted lines 70 inFIG. 3 of the drawings.

CLOSING OPERATION During the closing operation, the operating mechanism12 effects clockwise rotative closing motion of the drive shaft 6, whichthrough the linkage 21 effects upward closing motion of both the movablecontact structure 54 and the movable operating cylinder 26. This actioncontinues until the movable and stationary contact structure 37a. 40abut, as illustrated in FIG. 2, and continued upward closing motion ofthe operating cylinder 26 causes a desired compression of thecompression spring 27, thereby effecting a proper contact pressure inthe closed-circuit position, as illustrated in FIG. 2 of the drawings.

It will be noted that the interrupter 1 has both the stationary andmoving contacts hollow, and that in the closed-circuit position (FIG. 2)the volume 50 in the cylinder chamber system 26 is sealed off from therest of the circuit breaker interior 71 by virtue of the abuttingengagement of the stationary and movable contact structure 37a, 40, aseffected by the contact compression afforded by the contact compressionspring 27. The provision of the lost-motion connection 52 and thecontact compression spring 27 permits the contact motion to lag behindthat of the operating cylinder 26 during the initial part of the openingoperation, so that a higher pressure differential can be produced atcontact part by the choice of the length of the slots 55, and also bythe fact that there are no open ports of any kind before contact part.Additionally, it will be noted that there is no arcing 60 during theearly stages of gas compression when are interruption would not bepossible because of the low pressure available. Moreover, the contactpart speed can be higher since there will be an instantaneous momentumtransfer when the pivot pin 22 reaches the lower ends of the slots 55.Also the energy obtained from the contact compression spring 27 is usedto obtain the opening motion of the movable contact structure 54.

When all of the moving pans have reached the fully opencircuit position70, and crank motion is arrested by the external mechanism 12 (FIG. 1),the mass of the moving contact assembly 54 will act on its mechanicaltrain through the contact compression spring 27, thus diminishing theforces necessary to decelerate all the moving parts.

From the foregoing description of the invention, it will be apparentthat there is provided a delayed-action piston-type circuit interrupterl in which the gas is not permitted to flow from the operating cylinder26 until the pressure within the cylinder 26 has reached the valuerequired for efficient arc interruption. This results in a maximum useof the available gas, and also makes interrupting action easier becausethe interrupting region has not been contaminated with ionization causedby arcing prior to the time that sufficient pressure differential hasbeen generated to effect interruption.

Although there has been illustrated and described a specific structure,it is to be clearly understood that the same was merely for the purposeof illustration, and that changes and modifications may readily be madetherein by those skilled in the art without departing from the spiritand scope of the invention.

We claim:

1. A gas-blast circuit interrupter including, in combination, meansdefining a stationary contact structure having an exhausting ventaperture therethrough, an elongated insulating nozzle member (67), acooperable movable tubular venting contact (37) movable longitudinallyinteriorly within said nozzle member (67) at all times during arcing,said movable contact making closed abutting valvelike engagement withsaid vented stationary contact in the closed position, puffer pistonmeans for generating gas pressure at the point of separation between theseparable contacts and within said insulating nozzle member, operatinglinkage means having a lost-motion connection between the puffer pistonmeans and the movable tubular venting contact, whereby operation of theoperating linkage means first generates gas pressure within the noulemember while the separable contacts remain closed, thereby preventing anexhausting flow of gas through the contacts at this time, and followingtakeup of the lost-motion, separation of the contacts results with allof the gas blast compelled to flow through both separable ventedcontacts to thereby sweep the arc interiorly within both vented contactsnear a current zero for quick interruption.

2. The combination according to claim I, wherein the elongatedinsulating nozzle member (67) is stationary.

3. The combination according to claim I, wherein the stationary contactstructure supports the elongated insulating nozzle member (67).

4. The combination according to claim 1. wherein the puffer piston meanscomprises an operating cylinder slidably movable over a stationarypiston secured to the stationary contact structure.

5. The combination according to claim 1, wherein the lostmotionconnection of the operating linkage means comprises a biasing spring(27) which biases the movable contact (30) toward the closed-circuitposition.

6. The combination according to claim I, wherein the stationary contactstructure is supported by an elongated support member (41 and thepufi'er piston means comprises a movable piston member which is guidedby sliding over the stationary contact support (41).

7. The combination according to claim 1, wherein the puffer piston meanscomprises an operating cylinder which slides over a stationary pistonsecured to the stationary contact structure, and the other end of theoperating piston has a support member to which operating links (21) aresecured.

8. The combination according to claim I, wherein the movable ventedcontact (30) never withdraws from the elongated insulating nozzle member(67).

9. The combination according to claim I, wherein the stationary andmovable contact structure is disposed interiorly within an elongatedouter insulating casing (3), and the insulating casing (3) has aterminal plate closing one end thereof and has a crank casting closingthe other end of the casing (3) with crank means for the operatinglinkage disposed therewithin.

10. The combination according to claim 1, wherein a fixed piston and thefixed nozzle member (67) are secured to the relatively stationarycontact structure.

11. The combination according to claim I, wherein a cooling structure(46) is secured to the stationary contact structure. and the gascompressed by the puffer piston means is compelled to traverse thecooling structure prior to entry into the arcing region.

12. The combination according to claim 1, wherein the lostmotionconnection comprises spring-biasing means to bias the movable contactagainst the stationary contact in the closedcircuit position of theinterrupter.

13. The combination according to claim 1, wherein the puffer-pistonmeans comprises an elongated operating cylinder (26), and an elongatedouter insulating casing (3) is provided having slight clearance betweenit and the inwardly disposed longitudinally movable operating cylinder(26), and a stationary piston structure is secured to the stationarycontact and assists in guiding the longitudinal motion of the operatingcylinder 26).

